.cropHandler {
    position: absolute;
    cursor: move;
    background-image: linear-gradient(to right, #fff 50%, #444 50%), linear-gradient(to right, #fff 50%, #444 50%), linear-gradient(to bottom, #fff 50%, #444 50%), linear-gradient(to bottom, #fff 50%, #444 50%);
    background-size: 10px 1px, 10px 1px, 1px 10px, 1px 10px;
    background-repeat: repeat-x, repeat-x, repeat-y, repeat-y;
    animation: marching-ants 1s linear infinite;
}

@keyframes marching-ants {
    from {
        background-position: 0 0, 0 100%, 0 0, 100% 0;
    }
    to {
        background-position: 20px 0, -20px 100%, 0 -20px, 100% 20px;
    }
}